When laying a new floor or repairing an existing one, it’s easy to underestimate the importance of proper prep work. But when it comes to using self-levelling compounds, preparation is essential. Whether you're working on a small bathroom, garage, large commercial space, exterior area, or underfloor heating installation, taking the right steps at the start ensures smooth, durable, long-lasting results.

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The Benefits Of Prepping Your Floor

Self-levelling compound forms the base of your flooring system. Whether you're laying carpet, tiles, wood, or stone, proper floor preparation affects everything, from how easily the flooring goes down to how long it lasts.

Even Finish

Prepping your floor correctly allows the compound to spread evenly, providing a flat, smooth surface.

Easier Installation

A level sub base speeds up the installation of your chosen flooring.

Improved Adhesion

Cleaning and priming the sub-base ensures a better grip for both primer and compound. It will also aid the flow of self-levelling compound, providing the best result possible.

Strength & Durability 

Poor preparation can lead to cracks, delamination, or a weakened bond, shortening the life of your floor.

Professional Results

A well-prepared surface ensures an even finish that looks great and performs well.

When To Use A Self-Levelling Compound?

Self-levelling compound is used for many flooring projects due to its versatility, effectiveness and ease of use. It can be applied to concrete, wood or tiled subbases for both internal and external flooring. However, self-levelling shouldn’t be used for structural support or areas with more than 5mm unevenness, traditional screed may be more suitable for the latter. 

The Tools You Need to Prepare Your Floors for SLC

• Personal protective equipment (PPE)

• Broom, dustpan & vacuum

• Angle grinder & grinding discs

• Scrapers

• Paddle mixer & mixing bucket

• Steel trowel

• Self-levelling compound

How to Prepare Your Floor for Self-Levelling Compound

Step 1: Remove Existing Flooring 

Remove any existing flooring, including carpet, tiles, vinyl, or tile adhesive, to create a clear, flat subbase for your self-levelling compound. Whilst it is possible to apply self-levelling to certain surfaces, full removal gives the best foundation for long-lasting results.

Always wear the appropriate PPE during this process. Rubber gloves protect your hands, while goggles and a dust mask help shield you from airborne particles and debris.

For tougher surfaces or stubborn residues, floor grinders like the BIHUI Concrete Grinder make light work of removing tiles, adhesive, natural stone, plaster, paint, coatings, and more, helping you prep efficiently and safely.

Step 2: Grind Rough Areas

Use an angle grinder fitted with the correct grinding disc for your surface type to remove high spots, rough patches, or exposed aggregates. Before grinding, lightly dampen the floor to help minimise dust. Once complete, make sure to vacuum thoroughly to remove all debris and ensure a clean, level surface for the next step.

Step 3: Clean Your Subbase

This is one of the most critical steps. Thoroughly cleaning and clearing your sub base ensures all dust, dirt, grease, and debris are removed from the area. Not only does this create a smooth surface for the self-levelling compound to adhere to, but leftover dirt or dust can weaken the bond, leading to peeling, cracking, or an uneven finish.

Start by using a dustpan and brush to clear larger debris, then follow up with a specialist commercial vacuum like the Rubi AS-30 Pro to remove finer particles from seams, edges, and surface pores. This ensures your subbase is properly prepped and ready for the next step.

Step 4: Fill Holes & Cracks

Carefully inspect the area for any holes, gaps, or cracks. These must be properly filled and sanded to create a smooth, even surface and to prevent the primer or self-levelling compound from seeping into any voids. Always allow the filler to dry fully before moving on to the next step.

For quick and reliable repairs, the ARDEX P 10 SR Rapid Hardening Crack Repair Kit is one of our most recommended and popular solutions.

Step 5: Prime the Area 

Most self-levelling compounds have a recommended primer. Applying this before your compound helps smooth the subbase and helps the compound stick. Follow the manufacturer’s instructions on applying primer effectively.

For example, Mapei's Ultraplan Renovation Screed 3240 recommends applying Mapei Eco Prim Grip Plus beforehand to achieve optimal results. Similarly, ARDEX A 38 MIX Ultra Rapid Drying Cement is best paired with ARDEX P 51, a water-based priming and bonding agent, to ensure the best results possible.

Step 6: Seal the Edges

Once the primer has fully dried, check the edges around the area and seal any gaps. Using expanding foam is a great option when sealing the perimeter. It will help to prevent the leveller leaking through any gaps between the substrate and walls. This will prevent your self-levelling compound from seeping into the gaps and keep your compound contained to the area. 

Step 7: Lay the Self-Levelling Compound

Now your floor preparation is complete, and your primer is dry, it’s time to apply your self-levelling compound. Here are some of our other guides you may find useful at this stage.

• Self-levelling compound for underfloor heating

• How soon can you walk on self-levelling compound?

• Everything you need to know about self-levelling compound

Shop Self Levelling Tools

Our Top Tips for Preparing Your Floor 

• Prep the area carefully.

• Read the manufacturer's instructions.

• Use high-quality products and tools.

• Use the correct type of primer and compound for your project, subbase and flooring material.

• Wear the correct clothing.

• Ensure the room is well-ventilated. 

If you’re ever unsure about which tools or materials to use, feel free to give our team a call on 01604 859800 - our team is happy to help.